Automatic oven for gas burning stoves



April 21, 1953 e. KLEIN AUTOMATIC OVEN FOR GAS BURNING STOVES INVENTOR. 6z/5/a1/ K262 BY v W 7 ATTOQNEY Filed Sept. 29, 1948 Patented Apr. 21, 1953 UNITED STATES PATENT OFFICE AUTOMATIC OVEN FOR GAS BURNING STOVES Gustav Klein, Elkins Park, Pa., assignor to Caloric Stove Corporation, Philadelphia, Pa., a corporation of Pennsylvania Application September 29, 1948, Serial No. 51,741

' 3 Claims. 1 Gas burning cooking stoves usually have a plurality of top surface burners, an oven or broiler compartment, a burner for heating said compartment and a continuously burning pilot burner for automatically igniting said top burners by means of the usual flash tube. In a stove of this type, it is desirable that the oven or broiler burner, also, be ignited automaticallywhen the gas is turned on. This can be done by providing a second flash tube leading from a point near the oven burner to a point near the conventional, continuously burning pilot burner which ignites the top surface burners of the stove. A conventional flash tube arrangement works satisfactorily in connection with the open, or unconfined top surface burners but it is not entirely satisfactory for use in connection with an oven or broiler burner. This is due to the fact that a relatively large volume of gas is discharged into the flash tube before the gas will reach the pilot burner on the top of the stove.

This is true in all cases, but more so when relatively heavy gases or mixtures of gases are used.

This difficulty can be overcome by allowing the pilot burner in the vicinity of the oven burner to burn continuously but, due to the large gas consumption entailed, and due to the heat and odors generated, particularly when certain gases or mixtures of gases are used, this arrangement, too, is not entirely satisfactory. Also, if such a pilot burner should go out, there will be an accumulation of gas in a confined space with the attendant danger of explosion.

To overcome this difliculty, heat responsive devices can be used to turn off the flow of gas to the oven burner pilot burner after the oven burner is turned off, or after the burner has been ignited, or both, but even then there will still be danger of explosion if the gas is turned on and off rapidly or before theheat responsive devices have'had time to reset themselves or to recycle. According to my invention, I provide the usual pilot and flash tube for initially igniting the oven burner, a relatively small pilot burner in the vicinity of the oven burner, means for Shiite ting the flow of gas to the flash tube when the oven burner is ignited and control devices for causing the small pilot burner to burn continuously as long as the oven burner is ignited and fora predetermined period of time after the oven burner has been turned off, said period of time being enough to allow the control devices to reset themselves or recycle.

. The nature. of the inventionand its advantages willgbe understood from the following specification and the accompanying drawings in which Fig. 1 is a schematic view of one of the invention.

Fig. 2 is a schematic view showing the relation of the parts to a burner located in the broiler compartment of a conventional cooking stove.

In the drawings I have shown only that much of the structure of a cooking stove as is absolutely necessary for proper illustration of the invention. For this purpose, there is shown a broiler compartment l6, an oven compartment 12 thereabove, top surface burners M, a burner 16 in the broiler compartment, a pilot burner 18 for automatically igniting the top burners l4, and a gas main 2E) for supplying gas to the burners l4 and I6 and to the pilot burner 18.

The flow of gas from the gas main 2!) to the burner I6 is controlled by a conventional combined valve and heat control device 22, which is connected by a pipe 24 to the gas main 2B. The device 22 is capable of shutting off the flow of gas completely or of allowing gas to flow in controlled quantities.

According to my invention, the valve and heat control device 22 is connected by a pipe 26 to a valve 28, which, in turn, is connected by a pipe 30 to the burner l 6. The valve 28 is so constructed that it normally assumes a closed position and is adapted to open and permit gas to flow to the burner [6 only under specified conditions. For the purposes of this invention, the valve 28 can be assumed to be controlled by a solenoid which acts to open the valve 28 when energized by electric current generated by a thera predetermined value. are available on themarket and therefore need not be shown or described in detail. v

The valve and heat control device 22 is also connected, by means of pipes 38 and 40 to a tipple ported pilot burner 42 and by means of a branch 44 to a compartment 48 which is formed in a casing 52. From the compartment 48 a pipe 54 leads to a pilot burner 55 located near one end 58 of a flash tube 59 the other end 60 of which is near the pilot burner l8 which is used for ignitingthe top burners M. Disposed near the upwardly pointing flame of embodiment compartment 55 formed in another portion of the" casing 52, and a pipe 76 leading from the compartment 15 to a pilot burner 18' disposed near the burner 16. The pilot burner 18 is relatively small and has a gas consumption whichgis con siderably smaller than that of pilot '56 or pilot.

42. The flow of gas from compartment to pilot burner '18 is controlled by a valve closure 68 which is also carried by rod 64 or by an extension thereof and which closes or opens pas,- sage 10.

In the drawings, the passages iii-and?! are shown as being formed in partitions Biland the rod 64 is shown as having hearings in the end walls 82. These, however, are merely illustrations and the structure can be varied at will.

However, in order to prevent leakage and still avoid the use of packing, which can be troublesome and which interferes with the free movement of the rod 64, I provide bellows Mandi-96 which are secured in air-tight mannerto adjacent walls or partitions of the casing 52- and to the rod 64 but which flex readily to permit movement of the rod 64. For example, the bellowed-i prevents gas from leaking at the point. at which the rod 54 enters the end wall of the casing- 52, and the bellows 86 prevents gas entering the compartment 48 from leaking. into compartment 15 and vice versa.

By this arrangement, if the heat control 22 is opened while the bimetal 62 is in the solid line position of Fig. 1 gas will flow through pipes 33 and! to pilot burner 42 and through pipe 44, compartment 48, and pipe 54 to pilot burner 56. The gas reaching pilot burner 56 is ignited by flash tube 59 andit ignites-the three way pilot burner 42.

' The heat from pilot burner 56,-when it happens to be ignited and from the downwardly pointing flame of the pilot burner s2 acts on the thermo couple (or pressure operated device) 32 to cause it to open the valve 28 and thus permit gas to flow to the burner l8 according tothe 'adjustment of the valve and heat control device 22. When'the gasreaches the burner 16, it is ignited by the laterally pointing flame of the tipple ported pilot burner 42. By the time this has taken place, a

the heat from the upwardly pointing flame ofthe tipple ported pilot-burner i2, and from the burner it, acts on the bimetallic element 62 andcauses it to move to the right, or from the solidto the broken line position in Fig. l. in other words, when the temperature of the bimetallic element is at, or below, a predetermined value, the bimetallic element will be inthe position shown in solid lines in Fig. l in which the valve closure 68 obstructs the passage i6 and the valve closure 66 does not obstruct the passage 1!. Under these conditions, the pilot burner-56 will remain ignited. Conversely, when the temperature ofthe bimetallic element 62- is at or above a predeter mined value, it moves to the broken line position in Fig. 1, in which passage H is obstructed by valve closure 66 and passage 2'!) is left open so that the gas flows directly, from the gas main it, through compartment 15, and pipe i6 to the relatively small. pilot burner it. Under these 4 conditions pilot burner 56 is extinguished and pilot burner 18 continues to burn as long as the temperature of the bimetal element 62 continues to be above the predetermined value, or as lon as the bimetal element is in the broken line position of Fig. 1. The pilot burner 42 continues to burn as long as the heat'control device 22 is open. 'When the-gas turned off by closing the valve and heat control 22, the burner l6 and the pilot 42' are extinguished but the pilot 16, which receives gas directly from the main 2%], through pipe", passage-Hi, compartment 15, and pipe 16 will continue to burn as long as the valve closu're 68 does not-close the passage 16 which,

inturn is-a's long as the temperature of the bim'etal elernent'62 is at or above the predetermined value- The temperature value to which the bimetal element is set is well below that at which the thermocouple 32, or its equivalent,

opens the valve 28. Therefore, any gas reaching the burner I6 through valve 28 will be ignited by pilot burner 18 instead of accumulating in the oven compartment and presentingan explosion hazard.

When the temperature of the bimetallic ele ment 62 falls below the predetermined'value, it moves back to the positionshown in solid lines in Fig. l in which only passage Ill is obstructed by valve closure 68. Under. these conditions, the pilot burner 18 is extinguished" and since the valve and heat control 22 is closed, the: pilot burners 42 and 56 also are extinguished. The cooling of the thermocouple 32. also closes the valve 28 and therefore no gas can reach the burner it even if the combined valveand heat control 22 is opened, and the stoveis ready for the start of another cycle of operation.

It will thus be seen that the burner 16 is automatically ignited by merely turning onoof the gas; that, between cooking operations, there is no constantly burning, pilot burnerinthe oven or broiler compartments, when these compartments are not inuse, that the relatively large, initial pilot burner.- 56 is extinguished very shortly after the burner It is ignited, and that' there is no danger of explosion due to the. admission of gasinto the burner compartment before the control devices have had time to'recycle; because such gas will: be ignited by pilot l8zwhich:continues to burn until the thermocouple 32, which is independent of the ambient temperature of the oven, has-cooled enough to permit valve" 28 to close and shutoff-the flow of gas totheburner l6. It will also be seen that my invention is carried out byme'ansof simple, compact and inexpensive parts and that the operation is wholly automatic.

By providing the pilot burner 42', the action or the bimetallic element 62 and theaction oftliermocouple 32 become entirely independent of the heat of the oven compartment which is generated by the burner 16. .For' example, thedownward projecting flame of pilot burner 42 .keeps thermocouple 32 at the desired temperature regardless of'the adjustment of the burner l6. Thus, if the oven temperature is brought down'to 70 de grees FE, the currentigeneratedby the'thermocouple, if any willnot sufiice to-keepthe valve 28 open. Conversely, the heat in the oven .m-i'ght, conceivably be suificient to keep the valve 28'open. Since neither of these contingenciesiis desirable, I calibrate the thermocouple forv operation under the direct flamev of pilot HWhichkeeps the temperature of the thermocouple vatia: value higher thanthe maximum temperature which the oven compartment can be raised by the burner [6. In other words because the thermocouple is arranged to operate at a high temperature, it will open valve 28 when pilot burner 42 is lit and will close valve 28 when the pilot burner 42 is extinguished without any reference to the burner I6. The same is true of the bimetal element 62 which also cycles, with the igniting and extinguishing of the pilot burner 42, at a temperature higher than the maximum temperature to which the oven compartment is raised and entirely independently of the burner l6.

What I claim is:

For use with a gas burning stove of the type which has a main surface burner, a first pilot burner for automatically igniting said surface burner, a main oven burner, a gas main for supplying gas to said top pilot burner and said main burners, and a manually operable control device interposed between said gas main and said oven burner for regulating the flow of gas to said oven burner, of means for automatically igniting said oven burner when said control device is opened while said first pilot burner is ignited, said means including a first normally closed valve interposed between said oven burner and said control device, a first heat responsive means located near said oven burner and operable when subjected to heat of a predetermined value to open said first valve, a second pilot burner also located near said oven burner, a flash tube leading from said sec-- ond pilot burner to said first pilot burner for igniting said second pilot burner, a first conduit for delivering gas from said control device to said second pilot burner, a third pilot burner also located near said oven burner, in igniting relation to said second pilot and in heating relation to said first heat responsive means, a second conduit for delivering gas from said control device to said third pilot burner, a fourth pilot burner located near said oven burner, in igniting relation to said third pilot burner, a third conduit for delivering gas from said gas main to said fourth pilot burner, a second valve operatively associated with said first and third conduits for selectively permitting or preventing flow of gas through either of said first or third conduits to either of the second or fourth pilot burner, respectively, and a second heat responsive means adapted to be heated by said third pilot burner and operable to move said second valve to a first position in which said third conduit is closed and said first conduit is open to permit gas to flow to said second pilot burner, as long as the temperature of said second heat-responsive means is below a predetermined value, and to move said second valve to a second position in which said first conduit is closed and said third conduit is open to permit gas to flow to said fourth pilot burner as long as the temperature of said second heat-re sponsive means is above said predetermined value.

2. The structure recited in claim 1 in which the first heat responsive means is heated by the flame of said third pilot burner and opens said first valve when said third pilot burner is ignited and closes said first valve when said third pilot burner is extinguished regardless of whether said oven burner is ignited or extinguished.

3. The structure recited in claim 1 in which said second heat responsive means is heated sole- 1y by the flame of said third pilot burner and moves said actuating means to said first position when said third pilot burner is extinguished, and to said second position when said third pilot burner is ignited, regardless of whether said oven burner is ignited or extinguished.

GUSTAV KLEIN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,979,857 Benson Nov. 6, 1934 2,063,834 Bast Dec. 8, 1935 2,443,892 Caparone June 22, 1948 2,506,403 Witzel May 2, 1950 

